1. Field of the Invention
The present invention relates to a probing method and a probe apparatus.
2. Description of the Related Art
As is known, in the manufacturing process of a semiconductor wafer and the like, probe inspecting steps of inspecting the electrical characteristics of the manufactured semiconductor wafer on the wafer are performed.
An apparatus used for the probe inspecting steps has a structure in which the above characteristics are measured by bringing probe needles into contact with the electrode pads of each of a large number of elements, e.g., integrated circuit chips, on the semiconductor wafer and connecting the probe needles to a tester.
Therefore, the semiconductor wafer is kept held on a wafer chuck, e.g., a vacuum chuck. Alignment of the electrode pads and probe needles, i.e., setup, is performed by adjusting the position of the wafer chuck in the X and Y directions and the .theta. direction which is the rotating direction around the Z axis.
When measurement is actually performed, the wafer chuck is moved upward to obtain contact between the electrode pads and probe needles, and thereafter the wafer chuck is further moved upward, i.e., is over-driven to remove oxide films on the surface of the element, thereby assuring contact between the electrode pads and probe needles.
Alignment of the electrode pads of a circuit chip of the semiconductor wafer and the probe needles described above is executed when the type of the circuit chip as the measurement target is altered or when the type of the probe needles is altered in accordance with this type alteration.
This alignment must have a very small precision displacement. Conventionally, position adjustment is mainly performed by an operator's manual operation. More specifically, the operator performs alignment while observing the contact state of the probe needles with the electrode pads of the circuit chip by using a microscope or the like. Accordingly, this operation naturally requires a high skill.
Alignment requires a skill due to the following reasons. Namely, a probe card incorporating probe needles has an inclination in the rotating direction, i.e., has a position displacement that needs so-called correction. The position of an electrode pad of an integrated circuit chip is displaced from the position of a corresponding probe needle of the probe card. Since the number and pitch of pins of the circuit chip have increased, it is difficult to align all the electrode pads with the needles of the probe card at once.
It is thus demanded to automate this alignment process. However, to execute the alignment automatically, the following requirements must be satisfied.
A probe needle sometimes causes a contact failure due to deterioration over time. More specifically, due to wear, deformation, breakdown and the like of the needle point, the distance from the needle point to the electrode pad changes, and an appropriate contact state cannot be maintained.
For this reason, a probe card incorporating probe needles must maintain a fixed positional relationship between the electrode pads and probe needles not only when the type of the circuit chip is altered but also when circuit chips of the same type are to be inspected. Naturally, the probe needles are preferably exchanged after every predetermined cycle considering the service life of the probe needles, which is shortened by wear and the like.
It is, therefore, preferable in terms of the original purpose of automation that the alignment be automatically performed in every case including the above case of probe card exchange.